Selective remote control system



J- H. HAMMOND, JR

SELECTIVE REMOTE CONTROL SYSTEM June 24, 1952 Filed May 2'7, 1948 PULSETRANSMH'TER (SIGNAL).

R E wq u FP R T 5mm lmAm I one PTF a E m N M m n C N w m. m R 5 mm m R n5 3M G a) I II F vm N K a a M HY M a 5 A G ,H 2 H c R m Q m s. H N .\I 23 N l H 0 6 J 3 ,.L R m R O Wm M [N R n m n E T 6 R N 9 4 5 A F 0 0 B mn 4 .AT T T T3 0 I 46 0 0 3! w c q i? .3 0 wk. u o a b a A a w w w w w ww m v Patented June 24, 1952 SELECTIVE REMOTE CONTROL SYSTEM.

John Hays Hammond, J12, Gloucester, Mass.

Application May 27, 1948, Serial No. 29,530

3 Claims. 1

This invention relates to an electro-mechann cal remote control systemand more particularly to a system wherein the control is effected bymatching a pulse pattern at the transmitter and receiver.

In a copending application filed of even date herewith, Serial No.29,528, now U. S. Patent No. 2,583,373, issued January 22, 1952. I haveshown ,a control system in which control was exercised by use of twotrains of recurrent pulses, with a fixed time interval between thepulses of each train, one train being used to drive a synchronousreceiver mechanism and the other being used to actuate a photo lamp,with selective control in accordance with the position of the mechanismat the time of'flashing the lamp.

My present invention relates to a control system using two trains ofpulses, one for synchronizing a receiver mechanism but with the other asignal train for comparison with a train of pulses recorded on a movingmember of the receiver mechanism. The individual pulses of the signaltrain are notnecessarily evenly spaced or of uniform length, but mayhave a random type of pattern. The system provides for security ofcontrol and simplicity of construction.

In one embodiment two radio links are provided between the control pushbuttons and the work circuits to be actuated in accoxlance with thecontrol button used. One radio link provides synchronous operation oftransmitter and receiver mechanism while the other radio link providesfor transmission of a pulse train characteristic of the operationdesired, which is compared with a pulse train synchronously suppliedlocally at the receiver. If the individual pulses of the transmitted andlocally supplied pulse trains match in timing. the desired control willbe consummated. If there is no match the receiver continues to releaseother pulse trains for comparison purposes until the desired patternpresented by the transmitter is matched at the receiver. Thus thereceiver is constantly seeking a control signal from the transmitter andresponding when one is being sent. This method has the advantage thatthe number of electronic circuits is minimized, but it requires that thetransmitted signal be sent for a sufliciently long period of time sothat the receiver will have an opportunity to present the correctlocally produced train for comparison. An alternate method may employ amultiplicity of electronic circuits to each of which all the possiblelocally produced trains are presented simultaneously instead of insuccession. Other modifications are possible but the invention will beunderstood gram illustrating one embodiment of the invention.

2 Referring to the drawing more in detail, the pulse train forsynchronizing the transmitter and receiver mechanisms is generated inpulse train former In which may generate for example three equallyspaced pulses or any selective pattern for accurately triggering asynchronizer mechanism. The pulse train former Ill may be of the knowntype used in television transmitters for producing synchronizing pulses.The output of the pulse train former is connected to a standard radartype pulse transmitter II which is connected by the intervening mediumto the receiver l2 to re create the synchronizing pulse train in theinput to synchronizer II. The output of the pulse train former I0 isalso connected to a synchronizer ll. These two devices l3 and 14 may beof the same general nature to turn a receiver shaft 15 in step with atransmitter shaft l6 so that they have the same angular positions at alltimes. One type of pulse former and synchronizer for a mechanicallydriven member is shown in Hammond Patent No. 1,874,287, dated August 30,1932. The shaft l6 carries a plurality of records I! to 22 such as sixmagnetic blanks on which are recorded different pulse train patterns.The shaft 15 drives an endless record such as a magnetic tape or wire onwhich are recorded in succession all six of the records driven by shaftIt. The shaft I5 is so geared that any point of the receiver record 23moves around the path during six revolutlons of the transmitter shaftl6. Pickups 24 to 29 are provided for the transmitter records and pickup 30 for the receiver record, and adjustments may be made in thesynchronizing system so a voltage pulse is produced by the pickup 3!] atthe same time a voltage pulse is produced by one of the pickups at thetransmitter, due allowance being made for the time required fortransmission of radio signals. That is, the pulse pattern produced bythe receiver record 23 in the windings of pickup 30 may be identicalwith the pulse patterns produced by the transmitter records ll to 22 insuccession in the corresponding pickups 24 to 29. It will be understoodthat the discs H to 22 may have been used as master records by which thereceiver record 23 has been made up by successive recordings.

The pickups 24 to 29 all have one terminal connected to a contact of acorresponding push button, designated A to F for pickups 24 to 29respectively. The other contacts of these buttons are connected togetherand to an input terminal of a pulse type transmitter 3|. The otherterminals of the pickups are connected together and to the other inputterminal of the transmitter 3|. When one of the buttons, say B is closedas here shown, the transmitter 3| "will be pulsed in accordance with thevoltage pattern produced by the corresponding pickup, such as pickup 25for button B. This button should be held closed at least for more thansix revolutions of the shaft ii to give an opportunity for the receiverrecord 21 to match in its movement a train of pulses nal pulses aretransmitted to their respective receivers i2 and 32 over different radiochannels, so there is no confusion in diverting the desired pulses tothe desired circuits of th receiver. v

The pulse trains from the demodulator 33 and from the local recordpickup 30 are impressed upon the two inputs of a coincidental keycircuit 34 of well known construction, so designed that it produces anoutput pulse during the instants It will be understood that withsuitable design of the transmitters to take a suiiicient number ofpulses, it is possible to depress two or more control buttons suchvas Band D, causing operation oi. work circuits such as Wb and Wd during thea receiver cycle. This provides in effect for multiple control. Furtherit will be understood that I the receiver may utilize six records, sixwork circults, six coincidental keyers and six integrators if it isnecessary to cut down the time that a push buttonjshould be closedwithout charging the when pulses are simultaneously applied to the. two

inputs, but'produces no such output pulse when only one input pulse ispresent. Thu output pulses will be produced when the transmitted pulsetrain matches in timing the pulse train being picked up from the localrecord. In general the pulse patterns of the various transmitter Irecords and corresponding portions of the receiver records will not beofa constant interval type and moreover the time between pulses will be ingeneral much greater than the duration of a pulse. Therefore the outputof the coincidental key'circuit will be strong only when the part of thereceiver record being reproduced corresponds to the transmitted pulsepattern. This provides for selection of the pulse pattern andidentification of the control operation desired.

The output of the coincidental circuit 34 is impressed upon anintegrator or totalizer circuit 35 which produces a D. 0. output inaccordance with the time average of the output energy of thecoincidental circuit. For applying the D. C. output to the proper workcircuit, the shaft l5 which drives the receiverrecord also may operatethrough shaft 36, and intermittent mechanism 31, insulating coupling 38and shaft 39 to drive a distributor arm 40 with six contacts eachconnected to one terminal of two terminal work circuits Wa to Wf. theother ends of which are connature of the pulse trains. It will befurther understood that'the work circuits can include timing'circuitsrendering them operative for a longer period than that corresponding tothe operation of the coincidental key circuit.

This system is suitable for various selection and control systems suchas the control of the various elements of a radio relay station, atelenected to ground. One terminal of the integrator at thetransmitt'erby-use of a push button desired to operate that work circuit. In thepresent instance, the button B is depressed calling for operation ofwork circuit Wb. The pickup 30 has been producing a pulse train from thepart ofthe record-Which is identical with that being picked up by pickup24, but the coincidental circuits were not then effectively operatedbecause of the mismatch of the two trains of pulses.

Therefore work circuit Wa wa not energized when the distributorconnected the integrator 35 to thework-circuit Wa. But now the pickup 30is producing a pulse train corresponding to the pulse train whichisbeing transmitted over the signal channel due to closure of button B,there is a match ofthe two trains at the inputs of the coincidental keycircuit 34. and sufllcient D. C.

output is produced by the integrator 35 to actuate the work circuit Wb,to which the integrator is now connected.

typing system, receiver tuning or selection, control 01' moving objectsor in general any system requiring selection and actuation of a largenumberof work circuits. v

Various other modifications are possible as will be apparent to a personskilled in the art.

'Whatis claimed is:

1. A control system comprising a plurality of sources of'trains ofpulses, each havinga differently characterized time pattern meansconnecting one or more of said sources to actuate a transmitter, areceiver including a plurality of local sources of respective pulsetrains matching the pulse patterns of the various transmitter actuatingpulse trains, transmitter-receiver synchronizing means for releasin thepulse patterns of said trains from the local sources in sequencesimultaneously with the arrival of corresponding pulse patterns from thetransmitter, and receiver operated work circuits actuated in response tothe time coincidence of the pulses of the transmitted trains and thepulses of the locally released pulse trains, the work circuitcorresponding to a transmitted train being actuated only when the localpulse train being released matches .the transmitted pulse train.

2. A remote control system as set forth in claim 1 in which thetransmitter is adapted to radiate a repeated pulse pattern, said localsource generates the various pulse patterns in sequence, a plurality ofwork circuits are connected at the receiver in sequence corresponding tothe generated pulse patterns, and means responsive to a matching of thereceived and local pulse patterns actuates the work circuit connected atthat instant.

3. A remote control system as set forth in claim 2 in which the localgenerating means comprises a continuous recording and a switch device insynchronism with said recording connects the various work circuits tothe receiver in sequence.

JOHN HAYS HAMMOND, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 463,852 Bradley Nov. 24, 18911,193,807 Lyons Aug. 8, 1916 1,915,993 Handel June 27, 1933 2,256,487Moseley Sept. 23, 1941 2,369,783 Homrighous -1 Feb. 20, 1945 2,489,638Handschin Nov. 29, 1949 Finch Feb. 21, 1950 I

